We generally tend to believe that only one of them is important, because we don't know the other two, it is ignorance, but now we will talk about one of them :

The enteric nervous system

The enteric nervous system (ENS) is a subdivision of the autonomic nervous system, it is responsible for directly controlling the digestive system.

It is found in the sheaths of tissue lining the esophagus, stomach, small intestine and colon.

It is the main object of the study of Neurogastroenterology.

Structure

The NUS is quite large, and is composed of a network of millions of neurons, the thousandth part of the brain but in the spinal cord, and divided by the 7-8m digestive tract.

It is also a very complex system consisting of a neural network capable of acting independently of the brain, to remember, learn ..., sometimes speaks of "second brain".

This is a local, very systematically organized and capable of autonomous operation, connected to the central nervous system (CNS) via sympathetic and parasympathetic systems.

They send information to the small motor, while it sends sensitive information to the CNS.

ENS neurons are given in two types of ganglia: myenteric plexus and plexus submucales:

Submucosal plexus or Meissner.

It is a continuous network from the esophagus to the external anal sphincter located in the submucosa.

It is responsible for regulating the secretion of hormones, enzymes and all kinds of substance secreted by different glands located along the gastrointestinal tract.

Myenteric plexus or Auerbach, which lies between the circular and longitudinal muscle layers of the intestine are less in the esophagus and stomach, but are found abundantly in the small and scarce at the end of the anal canal.

It is responsible for gastrointestinal intrinsic movements.

These plexuses of the intestine, also have connections with similar plexus of the gallbladder, pancreas and even the sympathetic chain ganglia, para-aortic.

Includes or sensory afferent neurons, interneurons, and efferent or motor neurons, so that it can act as a central integrator of signals in the absence of CNS input and perform reflex actions

Functions

The SNE is responsible for autonomic functions such as coordination of reflexes, the peristaltic movements of the discharge regulation is very important in biliary and pancreatic secretion, peristaltic contractions and mass (in vomiting and diarrhea), is sensitive to hormones and so on.

Embryological development

There are very early migration of neural crest that populate the gut wall, is a very early stage and migrate at both ends of the digestive tract.

Through this crest migrate many cell lines, not only of this system. Enteric strains will be located in the plexus to visceral.

It is a migration of neural crest especially the romboencéfalo to the anterior 2 / 3 of the colon and neural crest from 1 / 3 of the colon to the anus.

Neurons will have the visceral plexuses of Meissner and Auerbach.

The enteric nervous system or "second brain" directly responsible for controlling the digestive system.

The importance of looking into the enteric nervous system would be that it ensures that the digestive functions remain integrated and coordinated operation.

Not only that, experts say.

Located inside the womb, the second brain is connected with the brain located inside the skull and at least in part, determines our mental state and plays a key role in certain diseases of the body.

Remain out of reach, despite the great impact that this neural network is to the body, the generation of conscious thought and decision-making, researchers say.

According to declare the subject matter expert Michael Gershon of Columbia University Medical Center, "the second brain does not help in the mental processes: religion, philosophy and poetry are in the hands of another brain."

This second brain contains about 100 billion neurons, which is more than the ones in the spinal cord or peripheral nervous system.

This huge amount of neurons in the enteric nervous system is what allows the digestion is done properly, the main brain without having to intervene in their processes: the breakdown of food, absorption of nutrients and removal of wastes require chemical processing, muscle, etc.. in charge of the second brain, independently.

But the complexity of the enteric nervous system does not end there, because this second brain also influences much of our emotions: the feeling of having "butterflies", for example, is actually a physiological signal that responds to a state nerves or stress, and we perceive through the nerves present in our intestines.

The complexity of the second brain does that, it depends in part on our everyday physical and emotional wellbeing.

Other current research trying to establish how the second brain involved in the body's immune response, given that 70% of our immune system focuses on the gut to expel and kill invaders.

Digestive functions require the coordinated and integrated operation of several subsystems of the digestive tract such as:

The mucosal epithelium.

The musculature.

Blood and lymphatic vasculature.

Glands.

This is carried out by a neural network whose centers are located in the gut wall (intrinsic innervation) and is connected to the central nervous system (extrinsic innervation) are responsible for maintaining an integrated activity of all the subcomponents of the tube tract.

Exception to that the upper third of the esophagus and pharynx, with only extrinsic innervation.